Issue 6665 - Optimize element hiding emulation filter lookups

lib/coreUtils.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 37 matching lines @@
 
   return -1;
 }
 exports.findIndex = findIndex;
 
 function indexOf(iterable, searchElement)
 {
   return findIndex(iterable, item => item === searchElement);
 }
 exports.indexOf = indexOf;
+
+function* filterIt(iterable, callback, thisArg)
+{
+  for (let item of iterable)
+  {
+    if (callback.call(thisArg, item))
+      yield item;
+  }
+}
+exports.filterIt = filterIt;
+
+function* mapIt(iterable, callback, thisArg)
+{
+  for (let item of iterable)
+    yield callback.call(thisArg, item);
+}
+exports.mapIt = mapIt;
+
+function* flattenIt(iterable, callback, thisArg)
+{
+  for (let item of iterable)
+    yield* item;
+}
+exports.flattenIt = flattenIt;
+
+function* regExpIt(regExp, string)
+{
+  let match = null;
+  while (match = regExp.exec(string))
+    yield match;
+}
+exports.regExpIt = regExpIt;